http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
Ohmic contact metallizations to phosphrous based compound semiconductors by solid phase regrowth
xviii, 166 leaves : illustrations ; 28 cm.
In this study, a new approach to form non-spiking and low
contact resistivity contacts to p-InP, p-InGaAsP, and n-GaP
will be investigated by utilizing solid phase regrowth
principle to enhance the tunneling current across the
barrier, thus resulting in ohmic contact behavior. P-type
indium phosphide (InP) and its related compounds, such as
InGaAsP and GaP have been widely used for the fabrication of
modern high speed electronic and optoelectronic devices. Low
resistance and reliable ohmic contacts are required for
superior device performance. The most common approach to
fabricate ohmic contacts to p-InP and its related compounds
involves the use of Au-based metallizations, such as Au:Zn
and Au:Be contacts. It is generally believed that Zn or Be
dopes the surface region of the substrates during annealing,
resulting in an enhancement of tunneling current which leads
to an ohmic behavior. Although Au-based p-type contacts
yield satisfactory contact resistivity, there are several
inherent problems, i.e., poor reliability, non-uniform
surface and spiking interface and deep protrusion of Au into
the substrate. These spikes and deep protrusions can cause
problems during device operations. Thus, significant effort
has been expended for the development of low resistance,
shallow and non-Au-based ohmic contacts to p-InP and its
related compounds. The new approach involves solid-phase
reactions which result in either a heavily doped surface
layer or a heterojunction on the substrates. Conventional
evaporation and lift-off processes can be readily used in
this approach to define the contact areas. Thus, non-spiking
ohmic contacts based on solid phase reactions appear to be
the simplest and, perhaps, the most practical schemes for
device applications. We have developed the low-resistance
and thermally stable non-spiking ohmic contact schemes based
on the solid phase regrowth principle: (i) the Ge/Pd/Zn/Pd,
Pd/Sb/Zn/Pd, and Zn/Pd contacts, to p-InP (ii) the Si/Pd and
Al/Si/Pd contacts to n-GaP, and (iii) the Si/Pd/Zn/Pd and
Ge/Pd/Zn/Pd contacts to p-InGaAsP. Also in order to further
reduce contact resistivity, other ohmic contact schemes such
as Au/Pd/Zn/Pd and Pd/Zn/Pd contacts to p-InGaAsP were
investigated. Abnormal lateral Zn diffusion for the annealed
Issued also on microfiche from University Microfilms Inc.
Includes bibliographical references: pages 156-165.